PSYC 385 Lecture Notes - Lecture 3: Richard Lewontin, Optimism, Convergent Evolution

• School: Simon Fraser University
• Department: Psychology
• Course: PSYC 385
• Professor: Timothy Racine

Document Summary

Psyc 385 - lecture 3 - evolutionary explanation & causation. An adaptation - inherited characteristic increasing organism"s survival & reproduction in ancestral environment. Tells us something about phylogeny - evolutionary relationships. Even though similarities/functions aren"t from direct descent, would see same structure as coming from convergence. Evolution arriving at same design b/c environment calls for certain design. Particular shape found to be advantageous for environment. Exaptations (gould & lewontin, 1979; gould & vrba, 1982) which come in 2 forms - pre- adaptations & spandrels. Not adaptations b/c natural selection did not shape phenotype for its current use. Pre-adaptations are selected for one function but used for a new function ( co- opted adaptations ) E. g. feathers seem first evolved for thermoregulation, but later provided possibility of flying. Spandrels are now useful, but not result of past function & are said to be non- adaptive in origin. E. g. brain size, language, music may all be spandrels.